Your Tuesday Afternoon Time Suck: Underwater AK Fun

Come on, you’ve been wondering all morning how the Rayleigh-Plesset equation describes cavitation clouds coming out of an AK-47 that’s fired under water. You have, haven’t you? Now you also know why Blofeld’s henchmen fought 007 and the good guys in Thunderball with spear guns and knives.


  1. avatar JMS says:

    Smarter Every Day is a GREAT YouTube channel. Lots and lots of really good content on there, from coiling honey to super duper crazy pixel image of Macchu Pichu to discovering new species of spiders to awesome super slow-mo video of bullets, hummingbirds, dragonflies, etc…. and all sorts of stuff… Lots of time to be spent on there 🙂

    In the first AK underwater video, you could really see the barrel flexing when fired. It was nuts. He also has an underwater revolver and pistol video(s).

  2. avatar ensitue says:

    Repeated firing under water WILL destroy that AK, the pressure is high enough that the gas piston/oprod nearly clears the receiver

    1. avatar Matt in FL says:

      I’m not sure he was terribly concerned.

      1. avatar ensitue says:

        It’s his dad’s rifle and not a cheapie either

        1. avatar Sean says:

          He said it was a Norinco on Reddit just with different furniture than your normal cheap AK.

        2. avatar Jeff says:

          The AK in the video is a Bulgarian Arsenal SLR-107. Not super spendy but not cheap either.

  3. avatar Tom in Oregon says:

    This is cool!
    I filmed my glock shooting underwater. Note to self. Keep ones head out of the water when shooting. The headache after was intense. Sound travels about 25 times faster underwater.
    Bullets don’t travel very far. Mine were bouncing off of a tree stump 5 feet away.

  4. avatar jwm says:

    That was great! That AK actually functioned well enough under water to cycle and eject the brass. I would have liked to see him run more than one round and see if the rifle actually functioned or jammed.

    Some guys have too much time on their hands. And we benefit from it.

  5. avatar Matt in FL says:

    That video had so many awesome things in it that I’m not going to try to count them. It was just awesome all around. Thanks.

    1. avatar Pantera Vazquez says:

      ^THIS……’nuff said……

    2. avatar Gyufygy says:


  6. avatar Sean says:

    Love this guys channel.

  7. avatar c4v3man says:

    Wonder how much lead and other contaminants is floating around in the pool after 5-10 rounds underwater… Wonder if the ammo he’s using is old enough to employ mercury in it’s primers.

    1. avatar William Burke says:

      Who is going to drink it?

  8. avatar RandallOfLegend says:

    My inner fluid dynamasist is happy. I never heard about the bubble cavitation equation, since my background was in aerospace, and exterior air flows.

  9. avatar mk10108 says:

    Total time suck…yes, but wonder if this can be applied to how the universe was created?

    1. Had the same thought. Those pressure clouds looked like mini big bangs.

      1. avatar William Burke says:

        Seriously, Dan, the Big Bang is BS, and one day everyone will know it. But I admit it looked like the POSTULATED Big Bang.

    2. avatar A. Nuran says:

      Don’t think so. We aren’t talking about temperatures high enough that the laws of physics are completely different.

    3. avatar Gyufygy says:

      Not sure about the Big Bang, but it does sound like how I understand supernovae work. It that case, the rebound is from the particles of the core being crammed so tightly by the star collapsing at a significant fraction of the speed of light, they physically cannot be compressed anymore, and most of that mass bounces right back out in a gigantic explosion.

      Physicists, feel free to rip this amateur a new one if I boned it up.

      No William, you don’t count as a physicist.

  10. avatar dwb says:

    great video.

  11. avatar IdahoPete says:

    From a practical after-action standpoint, I hope he dropped that rifle in a tub of Breakfree CLP or similar goop. Or at least a bucket full of kerosene.

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